This application makes reference to, incorporates the same herein, and claims all benefits accruing under 35 U.S.C xc2xa7119 from an application entitled Apparatus And Method For Detecting DVI Connectors Of A Digital Video Display Device earlier filed in the Korean Industrial Property Office on Nov. 17, 2000, and there duly assigned Ser. No. 2000-68440 by that Office.
1. Field of the Invention
The present invention relates to apparatus and method for detecting a DVI (Digital Visual Interface) connector of a digital video display device, and more particularly to apparatus and method for detecting a DVI connector of a digital video display device, which establishes a switching mode according to a type of DVI connector through the detection of the type of the DVI connector connected to a digital video display device and selectively displays on a screen a video signal input from an external signal source according to the established switching mode.
2. Description of Background Art
In general, an analog video display device having a cathode ray tube (CRT) and a digital video display device having a liquid crystal device (LCD) are widely used for a desktop computer and a portable (laptop or notebook) computer. Additionally, projectors are used with desktop or laptop computers. The digital video display device inputs and displays on the screen an analog video signal or a digital video signal from a signal source such as a graphic card of the computer main body.
The Digital Display Working Group (DDWG) has announced the standards of a Digital Visual Interface (DVI). The DVI specification provides a high-speed digital connection for visual display types that is display technology independent. The interface is primarily focused at providing a connection between a computer (workstation, desktop, laptop, etc.) and its display device (CRT, LCD, projector, etc.). DVI compliant host systems may provide either a digital only interface or a combined analog and digital interface. The case that the signal source supports only digital video signals is defined as DVI-D, and the case that the signal source supports all the digital video signals and analog video signals is defined as DVI-I.
The pin arrangements of the DVI-D type connector and the DVI-I type connector are shown in FIG. 5(a) and FIG. 5(b), respectively. The two defined connectors have the same physical outer dimensions. In each case the digital signals are present, allowing a monitor with a digital interface to attach directly to either type connector, however, the receptacle of a digital only monitor will not mate with the DVI-I connector because the receptacle of a digital only monitor does not have sockets for receiving the analog pins C1-C5 of the DVI-I connector.
FIG. 5(c) shows a monitor having a receptacle supporting connection to both the DVI-D connector and the DVI-I connector. That is, in the case that a signal source supports only the digital signals, the signal source is connected to a digital video display device as shown in FIG. 5 (c) through a DVI-D signal cable having a connector as shown in FIG. 5(a) or a DVI-I signal cable having the connector as shown in FIG. 5(b). Additionally, in the case that a signal source supports only analog signals or both the digital signals and the analog signals, the signal source is connected to a digital video display device as shown in FIG. 5(c) through a DVI-I signal cable having a connector as shown in FIG. 5(b).
Accordingly, an object of the present invention to provide apparatus and method for detecting DVI connectors of a digital video display device, capable of detecting a kind of a DVI connector connected to a digital video display device, setting a switching mode according to the kind of a DVI connector, and selectively displaying on a screen a video signal input from an external signal source according to the set switching mode.
In order to achieve the above object, an apparatus according to the present invention comprises an analog video processing unit for converting into a digital video signal as an output an analog video signal input from an external signal source through a connector; a digital video processing unit for decoding a digital signal input from the external signal source through the connector into a digital video signal, a horizontal synchronous signal and a vertical synchronous signal as outputs; a video signal switching unit for outputting a digital video signal input from the analog video processing unit if a first control signal is input, and for outputting a digital video signal input from the digital video processing unit if a second control signal is input; a synchronous signal switching unit for outputting a synchronous signal input from the external signal source through the connector if the first control signal is input, and for outputting a synchronous signal input from the digital video signal processing unit if the second control signal is input; a scaling unit for signal-converting the digital video signal input from the video signal switching unit as an output according to a pre-set resolution; a panel driving unit for displaying on a panel the digital video signal input from the scaling unit; a connector detecting unit for detecting whether the connector is the DVI-D type or the DVI-I type; and a controlling unit for outputting the first control signal or the second control signal to the video signal switching unit and the synchronous signal switching unit according to the detection result of the connector detecting unit.
In order to achieve another object of the present invention, in a digital video display device for, in case of an analog switching mode, displaying on a panel a digital video signal outputted from an analog video processing unit, and for, in case of a digital switching mode, displaying on the panel the digital video signal outputted from the digital video processing unit, a method according to the present invention comprises steps of: judging whether a connector connected to the digital video display device is the DVI-D type connector or the DVI-I type connector; setting a switching mode to a digital switching mode if the connector connected to the digital video display device is the DVI-D type connector as the judgement result; judging whether a synchronous signal is input through the DVI-D type connector after setting a switching mode to a digital switching mode; normally operating the digital video display device while keeping the pre-set digital switching mode if the synchronous signal is input through the DVI-D type connector; determining the occurrence of a malfunction to the digital video display device if the synchronous signal is not input through the DVI-D type connector, and power-saving-operating the digital video display device; judging whether the synchronous signal is input through the DVI-I type connector if the connector connected to the digital video display device is the DVI-I type connector; normally operating the digital video display device while keeping the pre-set switching mode if the synchronous signal is input through the DVI-I type connector, and, if the synchronous signal is not input through the DVI-I type connector, judging whether the pre-set switching mode is the analog switching mode or the digital switching mode; re-setting the analog switching mode to the digital switching mode if the pre-set switching mode is the analog switching mode or re-setting the digital switching mode to the analog switching mode if the pre-set switching mode is the digital switching mode; and returning to the step of judging whether the synchronous signal is input through the DVI-I type connector, and, if the pre-set number of repetition times is reached, determining the occurrence of a malfunction to the digital video display device and power-saving-operating the digital video display device.
Accordingly, the present invention detects the kind of a DVI connector connected to the digital video display device, displays on the screen a video signal input from an external signal source by performing the digital switching mode in case of the DVI-D type connector, and displays on the screen the video signal input from the external signal source by repeatedly performing the digital switching mode and the analog switching mode by the pre-set number of times and maintaining the switching mode at a position where a synchronous signal input exists, so that, in case that the present invention inputs only a digital signal from the external signal source through the DVI-D type connector, the input signal detecting steps can be removed to minimize a time loss and unnecessary parameter adjustment functions can be eliminated to minimize the user""s confusion.